[INFO] fetching crate narc_hal 0.1.3...
[INFO] testing narc_hal-0.1.3 against 1.55.0 for beta-1.56-1
[INFO] extracting crate narc_hal 0.1.3 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate narc_hal 0.1.3 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate narc_hal 0.1.3
[INFO] finished tweaking crates.io crate narc_hal 0.1.3
[INFO] tweaked toml for crates.io crate narc_hal 0.1.3 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded cortex-m-rt-macros v0.6.15
[INFO] [stderr]   Downloaded stable_deref_trait v1.2.0
[INFO] [stderr]   Downloaded vcell v0.1.3
[INFO] [stderr]   Downloaded r0 v0.2.2
[INFO] [stderr]   Downloaded cortex-m v0.5.11
[INFO] [stderr]   Downloaded aligned v0.2.0
[INFO] [stderr]   Downloaded bare-metal v0.2.5
[INFO] [stderr]   Downloaded cortex-m-semihosting v0.3.7
[INFO] [stderr]   Downloaded cortex-m-rt v0.5.7
[INFO] [stderr]   Downloaded stm32l0 v0.2.3
[INFO] [stderr]   Downloaded panic-semihosting v0.4.0
[INFO] [stderr]   Downloaded cortex-m v0.7.3
[INFO] [stderr]   Downloaded generic-array v0.13.3
[INFO] [stderr]   Downloaded volatile-register v0.2.1
[INFO] [stderr]   Downloaded bitfield v0.13.2
[INFO] [stderr]   Downloaded cortex-m v0.6.7
[INFO] [stderr]   Downloaded as-slice v0.1.5
[INFO] [stderr]   Downloaded aligned v0.3.5
[INFO] [stderr]   Downloaded cortex-m-rt v0.6.15
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3158f774fd9810fa04e67fbf397e40d083bea754a3008bbe8c76362b8de77c88
[INFO] running `Command { std: "docker" "start" "-a" "3158f774fd9810fa04e67fbf397e40d083bea754a3008bbe8c76362b8de77c88", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3158f774fd9810fa04e67fbf397e40d083bea754a3008bbe8c76362b8de77c88", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3158f774fd9810fa04e67fbf397e40d083bea754a3008bbe8c76362b8de77c88", kill_on_drop: false }`
[INFO] [stdout] 3158f774fd9810fa04e67fbf397e40d083bea754a3008bbe8c76362b8de77c88
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 52ce733d32abf995e74cbc6a48ed6e8c02c26f05a83230d2844a57e2fa7ba5c6
[INFO] running `Command { std: "docker" "start" "-a" "52ce733d32abf995e74cbc6a48ed6e8c02c26f05a83230d2844a57e2fa7ba5c6", kill_on_drop: false }`
[INFO] [stderr]    Compiling cortex-m v0.7.3
[INFO] [stderr]    Compiling nb v1.0.0
[INFO] [stderr]    Compiling vcell v0.1.3
[INFO] [stderr]    Compiling bitfield v0.13.2
[INFO] [stderr]    Compiling stable_deref_trait v1.2.0
[INFO] [stderr]    Compiling cortex-m-rt v0.6.15
[INFO] [stderr]    Compiling cortex-m v0.6.7
[INFO] [stderr]    Compiling cortex-m v0.5.11
[INFO] [stderr]    Compiling cortex-m-semihosting v0.3.7
[INFO] [stderr]    Compiling r0 v0.2.2
[INFO] [stderr]    Compiling aligned v0.2.0
[INFO] [stderr]    Compiling stm32l0 v0.2.3
[INFO] [stderr]    Compiling bare-metal v0.2.5
[INFO] [stderr]    Compiling generic-array v0.13.3
[INFO] [stderr]    Compiling cast v0.2.7
[INFO] [stderr]    Compiling cortex-m-rt-macros v0.6.15
[INFO] [stderr]    Compiling volatile-register v0.2.1
[INFO] [stderr]    Compiling nb v0.1.3
[INFO] [stderr]    Compiling embedded-hal v0.2.6
[INFO] [stderr]    Compiling as-slice v0.1.5
[INFO] [stderr]    Compiling aligned v0.3.5
[INFO] [stderr]    Compiling panic-semihosting v0.4.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/panic-semihosting-0.4.0/src/lib.rs:51:1
[INFO] [stdout]    |
[INFO] [stdout] 51 | #![feature(panic_handler)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]    |
[INFO] [stdout]    = help: the feature `panic_handler` has been stable since 1.30.0 and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `panic-semihosting` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "52ce733d32abf995e74cbc6a48ed6e8c02c26f05a83230d2844a57e2fa7ba5c6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "52ce733d32abf995e74cbc6a48ed6e8c02c26f05a83230d2844a57e2fa7ba5c6", kill_on_drop: false }`
[INFO] [stdout] 52ce733d32abf995e74cbc6a48ed6e8c02c26f05a83230d2844a57e2fa7ba5c6